Two former Merseyside care home workers, imprisoned for serious sexual offences against boys in their care, yesterday had their convictions quashed by the court of appeal. 

Basil Williams-Rigby, 57, was convicted of 22 counts of abuse and jailed for 12 years in August 1999. Michael Lawson, 62, who served with Liverpool police for 15 years before becoming a social worker, was convicted of 17 counts of indecent assault and jailed for seven years in June 2000. 

Both men are former colleagues of David Jones, now the Wolverhampton Wanderers manager, whose trial on similar charges in December 2000 collapsed after evidence that complainants had fabricated the allegations to secure large sums in compensation. 

The home at which the men worked cannot be named for legal reasons. 

Lord Justice Kennedy, who heard the appeals last month together with Mr Justice Crane and Mr Justice McCombe, noted that in both instances the crown case had depended on "the evidence of complainants, all of whom, by the time they gave evidence, had criminal records". 

He said in the case of Mr Williams-Rigby, fresh evidence had "undermined the evidence of two of the complainants", and as a result all the convictions were unsafe. 

A new witness, Wade Walsh, testified for Mr Lawson that another complainant had told him he was "brassed off" with the failure of the prosecution of Mr Jones, as he had been hoping to win compensation. The complainant also said he had fabricated his evidence against Mr Lawson to obtain money for a sex-change operation. 

The judges noted the jury in the Lawson trial was told "91 members of staff were under investigation and 20 had been arrested". In almost all cases, the inquiries were discontinued and the charges dropped. 

Chris Saltrese, solicitor for Mr Williams-Rigby said: "The convictions have been tragedies for both men. They have been stuck away in prison for more than three years for offences that never happened." 

The conviction of Mr Williams-Rigby led directly both to the formation of Fact (False Allegations against Carers and Teachers), a north-west campaign, and to the involvement of Claire Curtis-Thomas, MP for Crosby. 

The convictions of both Mr Williams-Rigby and Mr Lawson were obtained as a result of a Operation Care, in which police contacted former residents of the care home. Merseyside police said it was scrapping Operation Care last month, a day after the Williams-Rigby/ Lawson appeals. 

"These investigations have been a huge waste of public resources," said Mr Saltrese, who acts for several of those charged with abuse as a result of police "trawling". 

"The continuing tragedy is that there are dozens of people in the same position - doing prison sentences for phantom crimes. You have teams of detectives working to uncover crimes that never happened." 

The mounting concern led to an inquiry by the Commons home affairs select committee. Its report, published last October and now being studied by the Home Office, concluded that police trawling had led to "a new genre of miscarriage of justice". 

Ms Curtis-Thomas said: "The vast majority of men with whom we are concerned have been jailed for up to 18 years solely on the verbal evidence of complainants who are either prisoners or are already known to the police, concerning events alleged to have taken place up to 40 years ago." 

"We are worried that the police have unfettered and unmonitored access to so vulnerable and corruptible a group of witnesses." 

Next week the MP will present a dossier of 30 cases of concern to the criminal cases review commission.